People who need vision correction often want to change their eye color, but wearing two pairs of contact lenses simultaneously is unsafe. This practice, known as “stacking” or “doubling up,” is strongly discouraged by eye care professionals. Combining a prescription corrective lens with a colored cosmetic lens creates severe health risks for the eye. The direct answer is that you absolutely cannot stack a colored contact lens over a prescription one.
Doubling Up: Physical Constraints and Oxygen Deprivation
Stacking two lenses on the cornea immediately doubles the thickness of the material covering the eye, which creates a dangerous physical barrier. This increased thickness severely restricts the flow of oxygen to the cornea, the clear, dome-shaped front surface of the eye. The cornea receives most of its oxygen directly from the air. Layering two lenses drastically reduces oxygen transmissibility, leading to a condition called corneal hypoxia.
The lack of sufficient oxygen causes the cornea to swell, a reaction known as edema. This swelling can result in blurred vision. Furthermore, contact lenses are precisely measured to fit the individual curvature and diameter of a single eye; introducing a second lens disrupts this fit entirely. The two lenses will rub against each other and the eye, increasing friction and causing mechanical irritation, shifting, and potential adherence to the eye in an improper position.
Severe Eye Health Consequences
The resulting oxygen deprivation and poor fit lead directly to severe health consequences that can cause permanent vision damage. Hypoxia compromises the cornea’s natural defenses, making the eye significantly more vulnerable to infection. The space between the two lenses can trap debris, microorganisms, and old tear film, creating a warm, moist environment ideal for bacterial growth.
This situation dramatically elevates the risk of microbial keratitis, a serious infection of the cornea that can lead to a corneal ulcer. A corneal ulcer is an open sore on the eye’s surface that is painful and can cause scarring that permanently blocks vision. Chronic hypoxia may also trigger neovascularization, where new, abnormal blood vessels begin to grow into the clear cornea in an attempt to supply it with oxygen. These vessels obstruct vision and, once established, are often irreversible, threatening the clarity of the eye.
Prescription Colored Lenses: The Safe Option
A safe alternative exists for individuals seeking both vision correction and a change in eye color: prescription colored contact lenses. These lenses are manufactured with both the desired color tint and the necessary refractive power built into a single lens. This design ensures that the lens maintains the proper thickness and oxygen permeability required for healthy wear.
All contact lenses, including purely cosmetic or decorative ones, are classified as Class II medical devices by the U.S. Food and Drug Administration (FDA). This classification means that a valid prescription and a professional fitting from a licensed eye care provider are mandatory for their purchase and use. Adhering to the eye care professional’s instructions for wear and cleaning is the only way to safely combine vision correction with a cosmetic change.